Technical Specification
Quarter
Brick
Over-Temperature Shutdown value. It will allow the converter to
turn on again when the temperature of the sensed location falls
by the amount of the Over-Temperature Shutdown Restart
Hysteresis value.
48Vin 15Vout 6.7A
More detailed information is available in the application note
titled “EMI Characteristics” on the SynQor website.
APPLICATION CONSIDERATIONS
Input System Instability:
This condition can occur
because any DC/DC converter appears incrementally as a
negative resistance load. A detailed application note titled
“Input System Instability” is available on the SynQor web site
(www.synqor.com) which provides an understanding of why
this instability arises, and shows the preferred solution for cor-
recting it.
Application Circuits:
Figure D below provides a typical cir-
cuit diagram which details the input filtering and voltage trim-
ming.
Input Filtering and External Capacitance:
Figure E
below provides a diagram showing the internal input filter com-
ponents. This filter dramatically reduces input terminal ripple
current, which otherwise could exceed the rating of an external
electrolytic input capacitor. The recommended external input
capacitance is specified in the “Input Characterisitcs” section.
Electrolytic
Capacitor
V
in(+)
V
out(+)
V
sense(+)
R
trim-up
or
V
in
External
Input
Filter
33µF
ESR
≅1Ω
ON/OFF
Trim
V
sense(
_
)
V
in(
_
)
V
out(
_
)
R
trim-down
C
load
I
load
Figure D:
Typical application circuit (negative logic unit, permanently enabled).
L
V
in(+)
C
V
in(
_
)
Figure E:
Internal Input Filter Diagram
(component values listed on page 3)
.
Product # PQ48150QGA07
Phone 1-888-567-9596
Doc.# 005-2QG415D Rev. D
8/16/02
Page 11
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